Leukocyte dynamics in female reproductive health: roles and mechanisms

Leukocytes are critical mediators of immune responses and play multifaceted roles in female reproductive health, influencing processes such as menstruation, ovulation, implantation, pregnancy, and parturition. This review examines the dynamic involvement of key leukocyte populations, including neutrophils, macrophages, T lymphocytes, natural killer (NK) cells, and dendritic cells, across reproductive processes. Leukocytes contribute to tissue remodeling, hormonal regulation, immune tolerance, and pathogen defense. Dysregulation in their functions is implicated in reproductive disorders such as endometriosis, recurrent pregnancy loss (RPL), and complications arising from infections. The review integrates emerging insights into the molecular mechanisms governing leukocyte behavior, emphasizing the roles of cytokines, hormones, and chemokines in guiding their recruitment and activity. Key findings underscore the significance of leukocyte-mediated cytokine networks in maintaining immune homeostasis during pregnancy and their critical roles in spiral artery remodeling for fetal-maternal exchange. Neutrophils and macrophages support menstrual shedding and repair, while NK cells facilitate trophoblast invasion and placental development. Dysregulated leukocyte activity contributes to chronic inflammation in endometriosis and impaired immune tolerance in RPL. Additionally, leukocytes are central to immune defenses against infections, but excessive inflammation can lead to infertility or adverse pregnancy outcomes. Therapeutic strategies targeting these immune cells hold promise for managing reproductive health disorders by modulating inflammation, enhancing immune tolerance, and developing biomarkers for early diagnosis. In conclusion, leukocyte dynamics are integral to reproductive physiology and pathology, with significant potential for translational research to optimize reproductive health outcomes.